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US5003198A
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US
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Circuit technique for biasing complementary Darlington emitter follower stages
Assignee: Texas Instruments Inc
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Filing: 1989-09-28
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Granted: 1991-03-26
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Expires: 2009-09-28
Abstract
Abstract A circuit technique for biasing a complementary NPN-PNP Darlington Emitter Follower Stage without additional biasing resistors or current sources. Four diode-connected transistor are connected in series to provide biasing across the Darlington. Two transistors, one NPN and one PNP, are added with their bases and emitters connected in parallel with the top and bottom diodes, respectively, forming two current mirrors. The collector of the NPN transistor connects to the emitter of the first Darlington NPN transistor. The collector of the PNP transistor connects to the first Darlington PNP transistor. The current mirrors provide equal current to the two first Darlington transistors. These currents are also equal to the current through the four diodes for identically sized transistors.
Inventors
- 👤 Kenneth M. Bell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:35
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/51; H03K17/56; H03K17/60; H03K17/66; H03K17/665; H03K17/666; H03K17/667; H03K17/14; H03K17/615
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
67 words
A method of biasing complementary bipolar Darlington emitter follower stages, comprising the steps of: coupling a first current mirror to one of the Darlington stages; supplying current to the first current mirror; coupling a second current mirror to the other one of the Darlington stages; coupling a constant current active load to the second current mirror; and coupling the first current mirror to the second current mirror.
Claim 2
Independent Claim
67 words
A method of biasing complementary bipolar Darlington emitter follower stages, comprising the steps of: coupling a first current mirror to one of the Darlington stages; supplying current to the first current mirror; coupling a second current mirror to the other one of the Darlington stages; coupling a constant current active load to the second current mirror; and coupling the first current mirror to the second current mirror.
Claim 3
Dependent Claim
40 words
The method of claim 1, wherein the step of coupling the first current mirror to the second current mirror further comprises the step of: coupling a complementary pair of diode connected bipolar transistors between the first and second current mirrors.
Claim 4
Dependent Claim
25 words
The method of claim 1, further comprising the step of: coupling the first and second Darlington stages to first and second supply voltage sources, respectively.
Claim 5
Dependent Claim
74 words
A circuit for biasing complementary bipolar Darlington emitter follower stages, comprising: a first current mirror coupled to one of the Darlington stages; a first active device coupled to and providing current to the first current mirror; a second current mirror coupled to the other one of the Darlington stages; a second active device coupled to and providing current to the second current mirror; a bias circuit coupled between the first and second current mirrors.
Claim 6
Dependent Claim
74 words
A circuit for biasing complementary bipolar Darlington emitter follower stages, comprising: a first current mirror coupled to one of the Darlington stages; a first active device coupled to and providing current to the first current mirror; a second current mirror coupled to the other one of the Darlington stages; a second active device coupled to and providing current to the second current mirror; a bias circuit coupled between the first and second current mirrors.
Claim 7
Dependent Claim
18 words
The circuit of claim 4, wherein the bias circuit comprises a complementary pair of diode connected bipolar transistors.
Claim 8
Dependent Claim
33 words
The circuit of claim 4, wherein one of the Darlington stages is coupled to a positive voltage supply and the other one of the Darlington stages is coupled to a negative voltage supply.
Claim 9
Dependent Claim
98 words
A circuit for biasing complementary bipolar Darlington emitter follower stages, comprising: a first Darlington pair coupled between a supply voltage and an output node; a second Darlington pair coupled between a second supply voltage and the output node; a first current mirror coupled to the first Darlington pair; a second current mirror coupled to the second Darlington pair; a second active device coupled to and providing current to the second current mirror; a first active device coupled to and providing current to the first current mirror; and a bias circuit coupled between the first and second current mirrors.
Claim 10
Dependent Claim
98 words
A circuit for biasing complementary bipolar Darlington emitter follower stages, comprising: a first Darlington pair coupled between a supply voltage and an output node; a second Darlington pair coupled between a second supply voltage and the output node; a first current mirror coupled to the first Darlington pair; a second current mirror coupled to the second Darlington pair; a second active device coupled to and providing current to the second current mirror; a first active device coupled to and providing current to the first current mirror; and a bias circuit coupled between the first and second current mirrors.
Claim 11
Dependent Claim
18 words
The circuit of claim 7, wherein the bias circuit comprises a complementary pair of diode connected bipolar transistors.
Claim 12
Dependent Claim
17 words
The circuit of claim 7, wherein the first current mirror comprises a pair of PNP bipolar transistors.
Claim 13
Dependent Claim
17 words
The circuit of claim 7, wherein the second current mirror comprises a pair of NPN bipolar transistors.
Claim 14
Dependent Claim
29 words
The circuit of claim 7, wherein the first active device is coupled to a first signal input and the second active device is coupled to a second signal input.
Claim 15
Dependent Claim
143 words
A circuit for biasing complementary bipolar Darlington emitter follower stages comprising: a first Darlington pair of transistors having their collectors coupled to a positive voltage supply, the emitter of a first one of the pair being coupled to an output node; a second Darlington pair of transistors having their collectors coupled to a negative voltage supply, the emitter of a first one of the second Darlington pair being coupled to the emitter of the first one of the first Darlington pair; a first current operatively mirror coupled to the first Darlington pair; a first active device coupled to and providing current to the first current mirror; a second current mirror operatively coupled to the second Darlington pair; a second active device coupled to and providing current to the second current mirror; and a bias circuit coupled between the first and second current mirrors.
Claim 16
Dependent Claim
143 words
A circuit for biasing complementary bipolar Darlington emitter follower stages comprising: a first Darlington pair of transistors having their collectors coupled to a positive voltage supply, the emitter of a first one of the pair being coupled to an output node; a second Darlington pair of transistors having their collectors coupled to a negative voltage supply, the emitter of a first one of the second Darlington pair being coupled to the emitter of the first one of the first Darlington pair; a first current operatively mirror coupled to the first Darlington pair; a first active device coupled to and providing current to the first current mirror; a second current mirror operatively coupled to the second Darlington pair; a second active device coupled to and providing current to the second current mirror; and a bias circuit coupled between the first and second current mirrors.
Claim 17
Dependent Claim
28 words
The circuit of claim 12, wherein the bias circuit comprises: a complementary pair of diode connected bipolar transistors coupled in series between the first and second current mirrors.
Claim 18
Dependent Claim
52 words
The circuit of claim 12, wherein the second active device further comprises: a bipolar transistor having its emitter coupled to the positive voltage supply, its collector coupled to the second current mirror and the base of the second one of the first Darlington pair, and its base connected to a bias source.
Claim 19
Dependent Claim
52 words
The circuit of claim 11, wherein the first active device further comprises: a bipolar transistor having its emitter coupled to the negative voltage supply, its collector coupled to the first current mirror and the base of the second one of the second Darlington pair, and its base connected to a signal input.
Claim 20
Dependent Claim
44 words
The circuit of claim 11, wherein the first Darlington stage comprises a pair of NPN Bipolar transistors, with the emitter of the second one of the pair being coupled to the base of the first one of the pair and the first current source.
Claim 21
Dependent Claim
45 words
The circuit of claim 11, wherein the second Darlington pair comprises a pair of PNP Bipolar transistors with the emitter of the second one of the pair being coupled to the base of the first one of the pair and to the second current mirror.
Claim 22
Dependent Claim
52 words
The circuit of claim 12, wherein the second active device further comprises: a bipolar transistor having its emitter coupled to the positive voltage supply, its collector coupled to the second current mirror and the base of the second one of the first Darlington pair, and its base connected to a signal input.
Claim 23
Dependent Claim
52 words
The circuit of claim 11, wherein the first active device further comprises: a bipolar transistor having its emitter coupled to the negative voltage supply, its collector coupled to the first current mirror and the base of the second one of the second Darlington pair, and its base connected to a bias source.
References Cited (Backward Citations)
US4945259A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-03-25 | 1994-09-24 | 1995-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-03-25 | 1998-09-24 | 1999-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-03-25 | 2002-09-24 | 2003-03-26 | $7700.00 | Window Closed / Lapsed |